The present invention relates to carafes of the kind used for keeping coffee hot, and in particular to a new and improved vacuum carafe which can be used with a coffee-maker and which does not require a source of heat.
The existing kinds of vacuum carafes are primarily used in homes and for outdoor purposes, whereas offices, restaurants, etc., mostly use glass carafes kept warm on burners or electric heaters for making coffee. The existing vacuum carafes cannot in their present form be used directly with the type of coffee-maker that has the above-mentioned glass carafes. The coffee must first be prepared in a glass carafe and then poured into a vacuum carafe, if the coffee is to remain hot without continuous heating on a burner. Such vacuum carafes are often referred to as Thermos carafes.
There are several reasons why many restaurants and offices would prefer to make the coffee directly in a vacuum carafe. One reason is that coffee retains its taste and flavor better in a vacuum carafe than in a continuously heated glass carafe. Another reason is that there would be not need for burners or other sources of heat and that the coffee-maker could be manufactured without a carafe heat source, which would result in a simpler and less expensive device. A further reason is that a vacuum carafe can be brought to the place where the coffee is to be served and, once there, will maintain its serving temperature without any need for a heater. The fire hazard that exists when burners are used, is also eliminated. Evaporation from a continuously heated glass carafe and the ensuing concentration of coffee in the carafe are also eliminated.
The substitution of an ordinary vacuum carafe for the previously used glass carafe might seem to be a simple solution to this problem. However, this is not a good solution because of some inherent problems. If the use of the vacuum carafe is to be practical, it should not be necessary to remove the plug from the opening of the vacuum carafe before the brewing process and to put it back after completion of the brewing to maintain the temperature of the coffee, as is the case with an ordinary vacuum carafe. Furthermore, the vacuum carafe should be constructed in such a way that there be no overflowing of coffee in case someone should forget to remove the plug from the vacuum carafe before starting the brewing process. In addition, no complicated motions should be necessary for the serving of coffee.
The purpose of the present invention has therefore been to create a vacuum carafe which can be used for brewing from a coffee-maker directly into the carafe, which carafe at the same time does not require any manipulation or adjustment prior to or during brewing or during pouring.